Control of Hydrogen Sulfide in Oil and Gas Wells With Nitrite Injection

Computational Screening of Potential Inhibitors of Desulfobacter postgatei for Pyrite Scale Prevention in Oil and Gas Wells

10.1101/327957 ◽

2018 ◽

Cited By ~ 1

Author(s):

Abdulmujeeb T. Onawole ◽

Ibnelwaleed A. Husseinl ◽

Mohammed A. Saad ◽

Musa E.M. Ahmed ◽

Hassan I. Nimir

Keyword(s):

Hydrogen Sulfide ◽

Oil And Gas ◽

Gas Wells ◽

Atp Sulfurylase ◽

Sulfate Reducing ◽

Compound C ◽

Oil And Gas Wells ◽

Desulfobacter Postgatei ◽

Potential Inhibitors ◽

Reducing Bacteria

AbstractSulfate-reducing bacteria (SRB) such as Desulfobacter postgatei are often found in oil and gas wells. However, they lead to the release of hydrogen sulfide which in turn leads to the formation of iron sulfide scale such as pyrite. ATP sulfurylase is an enzyme present in SRB, which catalyzes the formation of adenylyl sulfate (APS) and inorganic pyrophosphatase (PPi) from ATP and sulfate which is one of the first steps in hydrogen sulfide production by D. postgatei. Virtual screening using molecular docking and machine learning tools was used to identify three potential inhibitors of ATP sulfurylase from a database of about 40 million compounds. These selected hits ((S,E)-1-(4-methoxyphenyl)-3-(9-((m-tolylimino)methyl)-9,10-dihydroanthracen-9-yl)pyrrolidine-2,5-dione;,methyl 2-[[(1S)-5-cyano-2-imino-1-(4-phenylthiazol-2-yl)-3-azaspiro[5.5]undec-4-en-4-yl]sulfanyl]acetate and (4S)-4-(3-chloro-4-hydroxy-phenyl)-1-(6-hydroxypyridazin-3-yl)-3-methyl-4,5-dihydropyrazolo[3,4-b]pyridin-6-ol), which are known as A, B and C respectively) all had good binding affinities with ATP sulfurylase and were further analyzed for their toxicological properties. The molecular docking results showed that all the compounds have negative binding energy with compound A having the highest docking score. However, based on the physicochemical and toxicological properties, compound C is the best choice as it does not violate any of the recommended properties that relate to absorption and distribution. Only compound C was predicted to be both safe and effective as a potential inhibitor of ATP sulfurylase. The binding mode of compound C revealed favorable interactions with the amino residues LEU 213, ASP 308, ARG 307, TRP 347, LEU 224, GLN 212, MET211 and HIS 309.ImportanceScale formation formed by hydrogen sulfide, which is produced by sulfate reducing bacteria such as Desulfobacter postgatei has been a persistent problem in the oil and gas industry leading to loss of money, time and even lives. The three selected hits from the virtual screenings of about 40 million compounds would possibly inhibit the enzyme, ATP sulfurylase, which is involved in the first reaction in hydrogen sulfide formation in Desulfobacter postgatei. The selected inhibitors are expected to significantly reduce the formation of hydrogen sulfide and consequently prevent the development of pyrite scale in oil and gas wells.

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A Blowout Accident Causative Model of Hydrogen Sulfide Oil and Gas Wells using DEMATEL and ISM Algorithms

10.2118/201032-ms ◽

2021 ◽

Author(s):

Chao Han ◽

Zhichuan Guan ◽

Yuqiang Xu ◽

Huaigang Hu ◽

Desong Wu

Keyword(s):

Decision Making ◽

Hydrogen Sulfide ◽

Oil And Gas ◽

Expert Knowledge ◽

Drilling Process ◽

Gas Wells ◽

Gas Field ◽

Network Diagram ◽

Causative Factors ◽

Oil And Gas Wells

Abstract Blowout is one of the most serious accidents in the drilling process of hydrogen sulfide (H2S) oil and gas wells, often accompanied by the leakage of H2S and other toxic gases, which easily causes casualties and huge economic and environmental losses. Therefore, this article uses DEMATEL and ISM hybrid algorithms to establish a blowout accident-causing network model for oil and gas wells with H2S content, thus strengthening the risk management. In this model, firstly, the general causative factors of blowout accidents are extracted by accident statistics. Secondly, expert knowledge is adopted to determine the correlation matrix among factors. Thirdly, based on the DEMATEL algorithm, the degree of the relationship among the factors is analyzed. The importance degree (centrality) of each factor and its status as well as role (causality) in the accident-causing system are given. Finally, the ISM algorithm is used to classify the factors and establish an accident-causing network diagram with hierarchical relationship. The proposed model has been applied in a gas field containing H2S in East Sichuan, China. The results show that causative factors of blowout accidents can be divided into cause group and effect group according to the influence relationship among them. The cause group implies the meaning of the causative factors, and the effect group denotes the meaning of the causative factors. Hence, it would be necessary to control and pay great attention to the cause group factors beforehand. The key causative factors of blowout accidents are geological exploration technology, safety monitoring facilities and on-site safety culture, which belong to the cause group and are at the basic level of the accident-causing network diagram. This model has provided effective decision-making guidance for HSE work in gas field and reduced the incidence of blowout accidents. This model uses a combination of qualitative and quantitative methods to analyze the causes of blowout accidents, not only considering the relationships between factors and accidents, but also considering the relationships between factors and factors. As a result, it provides decision-making basis for the prevention and control of blowout accidents in H2S oil and gas wells.

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A Proposed Standardized Static Laboratory Screening Test for Materials to Be Used as Inhibitors In Sour Oil and Gas Wells

CORROSION ◽

10.5006/0010-9312-16.2.107 ◽

1960 ◽

Vol 16 (2) ◽

pp. 63t-64t ◽

Cited By ~ 2

Author(s):

◽

Keyword(s):

Weight Loss ◽

Hydrogen Sulfide ◽

Laboratory Test ◽

Oil And Gas ◽

Rolled Steel ◽

Gas Wells ◽

Laboratory Screening ◽

Oil And Gas Wells ◽

Reproducible Method ◽

Cold Rolled

Abstract A description is given of a static laboratory test designed to provide a simple, easily reproducible method for screening materials to be evaluated subsequently as possible inhibitors in sour oil and gas wells. Mild cold rolled steel specimens were immersed for seven days in deaerated brine containing 400-600 ppm hydrogen sulfide plus kerosene. Materials suppressing 90 percent or more of the weight loss found in the control were deemed to be suitable for further study. 2.3.4

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